Have you checked your task bar for any "invisible" windows producing any buttons there? This strikes me as a case of the license agreement being drawn invisibly/ off screen and since you never confirm itr, Acro won't start. Perhaps resetting your graphics config might help, in case you e.g. had a 2 monito setup, but removed one of the monitors. Otehr than that this could be anything from UAC to security tools blocking stuff.... We realyl cannot know and a reinstall likely won't fix that particular issue, either.